The invention relates to a method for cleaning electrical contacts of an electrical switching device.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
In particular electrical contacts that are configured as power contacts and contactors are subject to age related wear depending on different factors for example temperature, switching currents, carrier currents, switching times, mechanical vibrations and other factors. After a certain aging and a certain number of switching cycles of the electrical contacts over their lifetime this wear leads to a failure of the electrical switching device due to contaminated and/or burned out contacts. Different measures are known to avoid or to remove contaminations and corrosion points on electrical contacts.
For example from U.S. Pat. No. 4,617,604 A a method is known in which an electrical switching device with a plurality of electrical contacts is partially switched in the currentless state—in order to protect the contacts—and is partially switched in the current applied state—in order to clean the contacts. Hereby the switching in the currentless state increases the service life of the electrical switching device but also leads to buildup of contaminations and/or oxide films. During switching in the current applied state these may be partially removed or reduced, which however—in particular as a result of the formation of electric arcs or arc discharges—leads to a shortened service life of the switching device.
It would be desirable and advantageous to provide a method for cleaning electrical contacts of an electrical switching device and a vehicle having such an electrical switching device, wherein the cleaning of the electrical contacts is performed in an alternative and preferably improved manner.